Clinical spectrum of primary hemophagocytic lymphohistiocytosis: experience of reference centers in Central and Southeast Anatolia.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease, with a high mortality if left untreated. In addition, the disease has unique diagnostic challenges. Therefore, despite the existing guidelines on management, current clinical practice data is informative on the course and outcome. Herein, a retrospective chart review study was conducted through the collaboration of six centers, located in central and southeastern Türkiye. The demographical data, laboratory results, and treatment outcomes were evaluated. Eighty-three patients were enrolled in the study. The mean age was 2 years, whereas the median age was 8 months with a range of a minimum of 1 week and a maximum of 12.6 years. Consanguineous marriage, history of sibling death, and familial history of similar disease were determined in 72.2% (n:60), 34.9% (n:29), and 39.8% (n:33) of the patients, respectively. The most common presentation was fever, followed by hepatosplenomegaly on admission. Disease-causing familial HLH variants were identified in 60.2% (n:50) of the patients. Hematopoietic stem cell transplantation (HSCT) was performed in 39.7% (n:33) of the cohort. The 2-year overall survival (OS) rate was 62.4% for the whole group. Comparing the patients who received HSCT and those who did not; the HSCT group had a 2-year OS of 84.7%, which was significantly better than patients who did not receive HSCT had a 2-year OS of 47.1% (p:0.001). Despite the improvement in HLH diagnostics and treatment options over the last decade, early death remains a leading problem for the survival of these patients. Therefore, appropriate assessment of the patients in experienced centers and HSCT are pivotal for better outcomes.